This invention relates to an apparatus and method for continuous deployment and stowage of an extendible nozzle of a rocket engine.
Rocket engines for vehicles operating around space stations, orbital transfer vehicles, and engines for high-orbit satellites use, during their operation, high expansion-ratio nozzles having greater length than the inner volume of their carrier allows. Therefore, the engine overall length must be reduced during transport, and then extended for operation. Furthermore, for vehicles which will travel at varying altitudes, it is not only desirable to simply deploy the extendible nozzle but it is also useful to be able to deploy the extendible nozzle to an optimal length depending on the altitude for high efficiency operation of the rocket engine. Several types of extendible nozzles have been disclosed; however, an effective adjustability feature which would allow for partial deployment of the extendible nozzle and retraction of the extendible nozzle back to a stowed position is lacking in prior art nozzle extensions.
For example, the present applicant has filed co-pending U.S. application Ser. No. 06/644,412, now U.S. Pat. No. 4,706,886, entitled, "Extendible Rocket Engine Nozzle", which discloses a telescoping sleeve section around the fixed nozzle of the rocket engine. The sleeve is driven to form the extendible nozzle. The extendible sleeve is advanced by inflating a pressure vessel which drives a support plate. The support plate supports radial-extending locking arms which engage the rear end of the extendible nozzle. After the nozzle has been extended, a second pressure vessel and latching mechanism is utilized to jettison all nozzle-extending and deployment components out of the extended nozzle.
The present applicant is also a co-inventor of the subject matter claimed in U.S. Pat. No. 4,638,947 entitled, "Pneumatic Bag Deployment of Folded Nozzle Extensions", which uses an inflatable bag to extend an extendible folded nozzle. The inflatable bag is located in the fixed nozzle and is jettisoned prior to the rocket engine being fired.
U.S. Pat. No. 3,711,027 issued to L. F. Carey, entitled, "Extendible Nozzle for Rocket Engines", discloses use of a frustoconical-shaped member formed of thin and light weight convoluted ductile sheet material, to comprise the engine nozzle wall structure which is adapted to be unrolled in crease-free manner. The device is arranged in combination with a temporary cover member which is so attached to the nozzle exit end portion thereof as to seal therein gas pressure sufficient to cause the nozzle structure to unroll in its extended configuration. The cover is then jettisoned so as to operatively open the nozzle.
U.S. Pat. No. 4,480,437, issued to P. D. Gauge, entitled, "Unfoldable Device for Extending the Nozzle of a Rocket Engine", discloses a device which consists of a frustoconical-shaped skirt formed by a stack of tube rings or coils welded to one another. The tube has a cross section flattened in the direction of the stack and incorporates a pyrotechnic device on the inside. The pyrotechnic device generates sufficient pressure to increase dimension of the tube in the direction of the stack. The effect of this pressure is to unfold the nozzle extension.
Although the Gauge '437 device can be inflated after initial rocket engine firing, it is limited to a single extension and cannot be stowed after this application. Thus, as in the other previously discussed references, nozzle deployment is non-repeatable and the nozzle is non-stowable after initial deployment.
U.S. Pat. No. 3,951,342, issued to W. H. Baker, Jr. entitled, "Entendible Nozzle for a Rocket Motor or the Like" discloses an extendible nozzle consisting of elongated petals representing strips of a conically shaped structure connected by means of hinges to the exit portion of the fixed nozzle. The Baker, Jr. extendible nozzle utilizes linear actuators to extend the nozzle. The acutators are released to retract the extendible nozzle with the assistance of a spring. Although the Baker, Jr. extendible nozzle is retractable, partial deployment does not provide utility because spaces remain between the petals until the nozzle is fully deployed.